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Item The Effect of HIV on the Microbiology of Adult Patients Presenting with Septic Arthritis at Chris Hani Baragwanath Academic Hospital(University of the Witwatersrand, Johannesburg, 2024) Gqamana, Loyiso; Ramokgopa, M.T.Background: Septic arthritis is an orthopaedic emergency that can result in severe morbidity and mortality if not managed timeously. Risk factor assessment of these patients is crucial in early diagnosis of the disease. Inflammatory septic markers (White cell count, C-reactive protein, and Erythrocyte sedimentary rate) have been found to assist in the process of making an early diagnosis. Human Immunodeficiency Virus (HIV) infection is known as a risk factor for septic arthritis. Immunosuppression that is observed with the HIV infection may lead to low septic marker values, resulting in a delay in confirming the diagnosis of septic arthritis. The markers of HIV infection such as Cluster of Differentiation 4 (CD4+) count and the viral load can be used to assist in the prediction of infection. Method: We conducted a retrospective study of patients who presented to the orthopaedic department at Chris Hani Baragwanath Academic Hospital (CHBAH) from 01 January 2015 to 30 June 2019 with septic arthritis. The clinical presentation; serological inflammatory marker; retroviral status with CD4+ count and viral load count; and post arthrotomy microbiology, culture and sensitivity were analysed. The sensitivity, specificity and likelihood ratios (LLR) for the inflammatory markers were calculated and compared to data published in the literature. The impact or association of the retroviral status with some of the categorical and continuous variables were assessed, to study if there were any differences in those variables when comparing the HIV-infected and HIV-non-infected patients. Finally, the microbiological growth results were compared between the HIV-negative, HIV-unknown and HIV-positive groups. Results: The prevalence of HIV-infected patients presenting with an osteoarticular infection was found to be 31.7% in our study population. A median CD4+ count of 281 cells per cubic millimeter with a median Viral Load (VLL) value of 2350 copies per millilitre was observed in our study sample. As a diagnostic test C-reactive protein, was found to have the best sensitivity (95%) and specificity (4.1%) out of all the inflammatory markers studied. However, the Likelihood ratio (LLR) for the diagnosis of septic arthritis by all inflammatory markers studied was low, making them poor diagnostic measures for the diagnosis of septic arthritis. Across the three groups of retroviral status in our study, i.e. HIV-negative, HIV-positive, and HIV-unknown; a finding of similar microbiological culture and sensitivity was observed. Gram-positive bacteria were cultured in 50% of the cases, with Staphylococcus aureus being the commonest bacteria grown. Despite having not occurred commonly pathogens such as Mycobacterium Tuberculosis (MTB), Acinetobacter Baumani, and Haemophilus influenza were also observed; and they were associated with patients who cultured polymicrobial organisms. Polymicrobial cultures with Gram-negative and atypical micro-organisms were observed to increase the likelihood for morbidity and mortality. The white cell counts, and erythrocyte sedimentary rate results were tested to be statistically significant with p-value = 0.025 (p < 0.05) and p-value 0.034 (p < 0.05), respectively. However, HIV status was not shown to have an impact on producing a positive or negative culture post arthrotomy. Conclusion: There was no difference in the overall cultured microbiology between HIV positive and HIV negative groups presenting with acute septic arthritis. However, it was noted that polymicrobial cultures were usually a combination of gram-negative and atypical bacteria. The latter was associated with HIV co-infection with CD4+ count of less than 200 cells per millimeter. The predictive power of inflammatory markers in making a diagnosis of septic arthritis was statistically significant in the HIV negative than the HIV positive group. All the studied inflammatory markers were seen to have low likelihood ratios